C130 power plant
I spent a day or so recently on the base at Brize. During the time there was a great deal of noise from engine runs by the C130 fleet at all times of day and evening.
From past types the only reason for a short engine run is after an engine change. Just out of interest does the C130 powerplant have poor reliability and lots of engine changes, or is there another technical requirement for the many tests/runs?